docstr: Returns a copy of column i of the matrix, as a (m x 1)
  CSR matrix (column vector).
docstr_tok: ["Returns","a","copy","of","column","i","of","the","matrix",",","as","a","(","m","x","1",")","CSR","matrix","(","column","vector",")","."]
code: def _getcol(self, i):
      """Returns a copy of column i of the matrix, as a (m x 1)
      CSR matrix (column vector).
      """
      M, N = self.shape
      i = int(i)
      if i < 0:
          i += N
      if i < 0 or i >= N:
          raise IndexError("index (%d) out of range" % i)
      indptr, indices, data = get_csr_submatrix(
          M, N, self.indptr, self.indices, self.data, 0, M, i, i + 1
      )
      return self.__class__(
          (data, indices, indptr),
          shape=(M, 1),
          dtype=self.dtype,
          copy=False,
      )
  
imports: import numpy
  from ._matrix import spmatrix
  from ._base import _spbase, sparray
  from ._sparsetools import csr_tocsc, csr_tobsr, csr_count_blocks, get_csr_submatrix
  from ._sputils import upcast
  from ._compressed import _cs_matrix
label_desc: Use image node_id 9 for calling the _csr_base obj's underlying member method code with example usage: obj._getcol(i) and returns: self